Device for the reconstruction of teeth

ABSTRACT

In a device for the reconstruction of missing or lost teeth, an implant, which ends in the gingival region, is biologically anchored in a jawbone. The implant itself comprises an implant body anchored in the jawbone and an implant head on the gingival aspect, acting as the anchoring site for an abutment, which in turn forms the reception site for the tooth being reconstructed. The abutment represents the retention shape of the tooth being reconstructed.

This application is a continuation of application Ser. No. 07/946,636,filed Sep. 18, 1992 now abandoned.

FIELD OF THE INVENTION

The present invention relates to devices and processes for thereconstruction of missing or lost teeth.

BACKGROUND OF THE INVENTION

In the reconstruction of missing or lost teeth according to present-daytechnique, an implant is secured to the patient's jawbone. This implant,which preferably is made of titanium or a titanium alloy, comprises ananchor pin anchored in the bone and a receiving funnel on the gingivalaspect, whose end is located in the gingival region below the gingivalcontour. An abutment, which preferably consists of titanium or atitanium alloy, is advantageously attached to the implant head via adetachable connection and represents the actual receiving core for areconstruction of a tooth or a bridging anchor. Towards the gingivalopening, this abutment has a thickening, which represents the actualreceiving site for the reconstructed tooth crown. The end of theabutment directed towards the oral cavity is firmly joined to thegingival opening of the tooth crown, preferably with the aid of abonding or screwing procedure. However, the tooth configurations of eachindividual assume different manifestations with regard to shape,geometric extent and position within the dental arch, for which reasondifficult adjustments are regularly required in the region of thethickening at the gingival aspect of the abutment if one wishes todeviate more or less, with the reconstructed tooth crown, from thepredetermined perpendicular indicated by the abutment anchored in theimplant head, or to change the root dimensions predetermined by theimplant post. The commercially available range of shapes allows littlescope for matching to the desired tooth/not shape and position of theneighboring teeth. This difficult adjustment consists, for example, inmaking an individual modification to the thickening at the gingivalaspect of the abutment, as recipient site for the reconstructed toothcrown, in order to effect a corresponding correction in the attitude andshape of the tooth being reconstructed. Clearly, such on-the-spotreworking poses considerable visual and technical demands, and this,with anything less than optimal performance of the correction, has animmediately negative effect on the quality of the work. A furtherimportant disadvantage of this concept is evident in that, with theslightest recession of the gingiva, the abutment will be exposed. Thiswill be evident in the form of a black linear arch above the gingivalboundary, which always leads to considerable impairment of the cosmeticappearance, something which frequently results in the existing conceptbeing unacceptable. Also, as intimated above, the last-named conceptdoes not permit any satisfactory correction of the gingival emergenceprofile.

SUMMARY OF THE INVENTION

The object of the invention is to provide a remedy for the defects ofprior tooth implants and procedures, and to provide a process by whichteeth to be reconstructed can be configured in an optimal fashion.

The essential advantages of the invention are that the basis of everyreconstruction is provided by an individual or standardized abutment,which is processed to a retention shape with regard to the final shapingof the tooth to be reconstructed, this shaping being carried outpreferably by machining with the aid of a copy-milling operation,preceded by a preliminary modeling of the individual form in wax orsynthetic material; a more expensive manual working is not excluded.Obviously, the abutment can also be shaped without cutting, for exampleusing a sinter technique.

A further essential advantage of the invention consists in the fact thatthere is the possibility of preparing the whole tooth reconstruction,i.e., abutment and tooth crown, in one piece so that the abutmentrepresents the actual reconstruction.

The following possibilities are available in principle:

A. The abutment comes ready for use with a retention shape.

The latter can be prepared ready-made or individually:

a) with a metal core, sheathing of ceramic, or a synthetic or of acomposite material;

b) completely of metal;

c) completely of ceramic, of a synthetic or of a composite material.

B. The abutment represents the actual individually preparedreconstruction of the tooth:

a) with a metal core; sheathing of ceramic, or a synthetic or of acomposite material;

b) completely of metal;

c) completely of ceramic, of a synthetic or of a composite material.

C. The abutment is fashioned as a telescope and used for providingdetachable prostheses.

In a preferred embodiment having a metal core, the sheathing has theform of an integral or quasi-integral jacket around the metal core. Inthe case of the quasi-integral embodiment, the jacket, composed of oneof the above-mentioned substances, reaches deep down into the anchoringregion of the abutment in such a way that, even if there is extensivegingival recession, no metallic exposure of the metallic core results,thereby maximizing the acceptance of the subject of the invention.

Since the retention shape corresponds exactly to the reconstruction withregard to shaping, any subsequent corrective adjustment of the abutmentis rendered superfluous. The very delicate alignment of the tooth beingreconstructed, to conform to dentition, is completely dispensed with,which in turn maximizes assurance of quality.

The above-mentioned embodiments are naturally also valid with regard tothe alignment of the abutment as a complete tooth reconstruction.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are illustrated in the drawings.All the elements which are not required for the immediate understandingof the invention have been omitted. In the drawings, the same elementsare provided with the same reference numerals in the various figures,and in which:

FIG. 1 is a partial cross-sectional view of an implant body anchored inthe jawbone;

FIG. 2 is a cross-sectional view showing an abutment anchored in theimplant, the abutment having a metal core with a sheathing of ceramic,synthetic or composite material;

FIG. 3 is a partial cross-sectional view of a reconstructed tooth inaccordance with this invention.

FIG. 4 is a partial cross-sectional view of a reconstructed toothaccording to another embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows the first step in the process of making a toothreconstruction. The gingiva 1 is prepared surgically between two healthyteeth 5, 6 sufficiently to allow the anchoring of an implant body 3 inthe jawbone 2. This implant body 3 has an implant head or socket 4secured at its gingival end, which serves as an aid to positioning andin this case has the shape of a hexagon. Obviously, other shapes can beused for the same purpose. It will always be necessary, however, toensure that the degrees of freedom between patrix and matrix are kept toa minimum. The socket 4 serves as an anchoring arrangement for anabutment 7, as shown in the following figures. The implant head 4 has ascrew thread 13, for receiving a detachable connection. Obviously, otherconnection arrangements can also be envisaged. Care must be taken toensure that the detachable connection will not work loose on its own.

Once healing has occurred following the insertion of the implant body,the abutment 7 may be fitted to the implant body as shown in FIG. 2. Theabutment 7 is fashioned as a retention shape and has a metal core 8 witha material sheathing 9 of ceramic, synthetic or composite material. Thehollow core 8 has a central aperture 12. As is clearly evident from FIG.2, the sheathing 9 reaches deep into the gingiva, i.e., approaching thearea of the jawbone, as seen in FIG. 4, which shows the sheath attachedaround the bottom portion of the core and extending an entire distancebetween a bottom end of a tooth 11 and a bottom end of the abutment 7.If subsequently, in the course of time, gingival recession occurs, atmost a region of the tooth-colored sheathing 9 of the abutment 7 will beexposed which will not cause any cosmetic impairment. The retentionshape of the abutment 7 can be prepared individually, i.e., any inclined(skew) plane that is required on the implant surface can be fashioned.In this way, optimal shape and attitude can be achieved in the toothreconstruction.

As FIG. 2 further shows, the connection between the implant body 3 andthe abutment 7 takes place exclusively in the metallic region of the twoconnecting pieces. A screw 10 is passed via the vertical aperture 12 inthe abutment 7 and screwed tight from above in the implant head 4. It isevident that the connection must not become unscrewed too easily on itsown. All necessary precautions known to the state of the art should beused to ensure that the joint between the implant body 3 and theabutment 7 can be unscrewed only by the use of special means. Thepositioning between the implant 3 and abutment 7 is carried out by thehexagonal recess at the lower end of the abutment 7 and the hexagonalshape of the implant head 4. The degrees of freedom between the head 4and the abutment 7 must be kept as small as possible, on the one hand tomaintain the predetermined position of the reconstruction and on theother hand to achieve support for the static connection. As alreadymentioned, other arrangements can also be envisaged withregard topositioning as well as coupling of the head 4 to the abutment 7, as longas the predetermined and defined purpose is still achieved.

In a modified form of the invention, the abutment 7 itself may take theform of the reconstructed tooth, including the aperture 12, which isalso present in this case, and which serves invariably for anchoring theabutment 7 to the implant head 4. The aperture 12 is closed, when thereconstruction is finished, at the open end with a plug-like insert ofthe same material as the abutment 7.

FIG. 3 now shows the final reconstruction, which is concluded by placingon a tooth crown 11. When comparing two existing healthy teeth 5, 6 anda reconstructed tooth 11, FIG. 3 itself clearly indicates the manifoldpossibilities that the described concept can open up and the maximalquality assurance that can thereby by achieved.

A device for the reconstruction of missing or lost teeth thus includesthe implant body 3, and means, such as an external thread on the body,for anchoring the body in a jawbone, and the implant head or socket 4 onthe body. The device further includes the abutment 7. Means, such as thescrew 10 and the screw thread 13 in the implant body 4, is provided forsecuring the abutment to the body, the abutment being non-rotatablerelative to the implant head. The device also includes the detachableprosthesis tooth 11 having a base and a cavity.

The abutment 7 includes the tubular portion 8 which is received in thecavity in the tooth. The tubular portion 8 is substantially the sameheight as a central portion of the tooth. The abutment 7 has the sheath9 formed on or attached to an exterior of the tubular portion 8, thesheath forming an abutment face spaced from the securing means 10 and13. The tubular portion 8 preferably has a narrow cylindrical upperportion, an enlarged bottom portion, and a curved transition cuffbetween a tubular portion and the bottom portion.

The sheath 9 is attached around the cylindrical portion and thetransition cuff. The size of an exposed portion of the sheath 9 belowthe abutment face is larger than an exposed portion of the tubularportion 8 below the abutment face. Put another way, the bottom end ofthe tooth 11 is spaced from the transition cuff, and a distance betweenthe bottom end of the tooth and the transition cuff is greater than adistance between the transition cuff and a bottom end of the abutment.The detachable tooth cavity has a length corresponding to the length ofthe tubular portion 8, and the base of the detachable tooth engages theabutment face.

Although a preferred embodiment of this invention has been illustratedand described herein, it is recognized that changes and variations maybe made without departing from the invention as set forth in the claims.

What is claimed is:
 1. A device for the reconstruction of missing orlost teeth, comprising: an implant body; means for anchoring the body ina jawbone; an implant head on the body; an abutment; means for securingthe abutment to the body, the abutment being non-rotatable relative tothe implant head; a detachable prosthesis tooth having a base and acavity; and the abutment including a tubular portion received in thecavity in the tooth, the tubular portion being substantially the sameheight as a central portion of the tooth, the abutment having a sheathformed on an exterior of the tubular portion, the sheath forming anabutment face spaced from the securing means, a size of an exposedportion of the sheath below the abutment face being larger than anexposed portion of the tubular portion below the abutment face, thedetachable tooth cavity having a length corresponding to the length ofthe tubular portion, the base of the detachable tooth engaging theabutment face.
 2. The device as claimed in claim 1, wherein theabutment, as a retention form of the tooth being reconstructed, is madeindividually for a patient.
 3. The device as claimed in claim 1, whereinthe abutment includes a metallic material.
 4. The device as claimed inclaim 1, wherein the abutment includes a ceramic material.
 5. The deviceas claimed in claim 1, wherein the abutment includes a non-metallicmaterial.
 6. The device as claimed in claim 1, wherein the sheath isformed of a tooth-colored material.
 7. A device for the reconstructionof a missing or lost tooth, comprising: an implant body, the implantbody including means for anchoring the implant body in a jawbone; anabutment, the abutment having a core, the core having a narrowcylindrical upper portion, an enlarged bottom portion, and a curvedtransition cuff between a tubular said narrow cylindrical upper portionand the bottom portion, and a sheath attached around the cylindricalportion and the transition cuff; means for non-rotatably anchoring theabutment to a top end of the implant body; a prosthesis tooth, the toothhaving a bottom end and a cavity extending into the tooth from thebottom end for receiving a portion of the abutment, the bottom end ofthe tooth being spaced from the transition cuff, a distance between thebottom end of the tooth and the transition cuff being greater than adistance between the transition cuff and a bottom end of the abutment;and means for securing the tooth to the abutment, wherein the core ismetallic.
 8. A device as claimed in claim 7, wherein the sheath isceramic.
 9. A device as claimed in claim 7, wherein the sheath istooth-colored.
 10. A device as claimed in claim 7, wherein the sheath isfurther attached around the bottom portion of the core and extends anentire distance between a bottom end of the tooth and a bottom end ofthe abutment.
 11. A device for the reconstruction of a missing or losttooth, comprising: an implant body, the implant body including means foranchoring the implant body in a jawbone; an abutment, the abutmenthaving a core, the core having a narrow cylindrical upper portion, anenlarged bottom portion, and a curved transition cuff between a tubularsaid narrow cylindrical upper portion and the bottom portion, and asheath attached around the cylindrical portion and the transition cuff;means for non-rotatably anchoring the abutment to a top end of theimplant body; a prosthesis tooth, the tooth having a bottom end and acavity extending into the tooth from the bottom end for receiving aportion of the abutment, the bottom end of the tooth being spaced fromthe transition cuff, a distance between the bottom end of the tooth andthe transition cuff being greater than a distance between the transitioncuff and a bottom end of the abutment; and means for securing the toothto the abutment, wherein the sheath is further attached around thebottom portion of the core and extends an entire distance between abottom end of the tooth and a bottom end of the abutment.
 12. A deviceas claimed in claim 11, wherein the sheath is ceramic.
 13. A device asclaimed in claim 11, wherein the sheath is tooth-colored.
 14. The deviceof claim 11, wherein said narrow cylindrical upper portion extends toapproximately the same height as the height of said sheath.
 15. Thedevice of claim 11, wherein said sheath includes an abutment face whichengages said bottom end of said prosthesis tooth, said narrowcylindrical upper portion extending above said bottom end of saidprosthesis tooth.
 16. The device of claim 11, wherein said distancebetween said bottom end and said transition cuff is less than the heightof said narrow cylindrical upper portion.
 17. The device of claim 11,wherein said narrow cylindrical upper portion is tubular.
 18. The deviceof claim 7, wherein said narrow cylindrical upper portion extends toapproximately the same height as the height of said sheath.
 19. Thedevice of claim 7, wherein said sheath includes an abutment face whichengages said bottom end of said prosthesis tooth, said narrowcylindrical upper portion extending above said bottom end of saidprosthesis tooth.
 20. The device of claim 7, wherein said distancebetween said bottom end and said transition cuff is less than the heightof said narrow cylindrical upper portion.
 21. The device of claim 7,wherein said narrow cylindrical upper portion is tubular.
 22. Anabutment for mounting a prosthesis tooth on a dental implant comprising:a. means for non-rotatably securing said abutment to said implant, b. ametal tubular portion having substantially the same height as thecentral portion of said tooth and an enlarged bottom portion forcontacting said implant, c. a non-metallic sheath formed on an exteriorof said tubular portion, the sheath forming an abutment face whichmounts said prosthesis tooth, said abutment face spaced from saidsecuring means of (a).
 23. An abutment of claim 22, wherein the exposedportion of the sheath below the abutment face is larger than an exposedportion of the tubular portion below the abutment face.
 24. An abutmentof claim 22, wherein said sheath is made of at least one of ceramic,synthetic material, or composite material.
 25. An abutment of claim 22wherein said means for non-rotatably securing said abutment to saidimplant comprises a screw engaging both said abutment and said implant.26. An abutment for mounting a prosthesis tooth on a dental implantcomprising: a. a metallic core having a narrow upper portion, anenlarged bottom portion, and a transition cuff between the upper portionand the bottom portion; b. a sheath made of at least one of ceramic,synthetic material, or composite material attached around the narrowerupper portion of the transition cuff, said sheath mounting saidprosthesis tooth.
 27. An abutment of claim 26, wherein the distance ofthe portion of the sheath below the bottom of said tooth and above saidtransition cuff is greater than the distance between the transition cuffand the bottom of the abutment.
 28. An abutment of claim 26, wherein thesheath extends around the bottom of said core to the bottom of saidabutment.
 29. An abutment for mounting a prosthesis tooth on a metaldental implant anchored in bone, said abutment comprising: a. a hollowmetal central core, said core having an upper portion which mounts saidtooth and an enlarged bottom portion for contacting said implant and atransition cuff between said upper portion and said bottom portion; b. ametal screw passing through said hollow central core for securing saidcore to said implant; and c. a sheath made of ceramic synthetic, orcomposite material surrounding at least the portion of said central coreand said transition cuff, said sheath forming an abutment face whichmounts said tooth, a portion of said sheath being exposed below thebottom of said tooth when said tooth is mounted on said abutment face.30. An abutment of claim 29 wherein said sheath extends to thesupragingival portion of said central core.
 31. An abutment of claim 29wherein said metal is titanium or titanium alloy.
 32. An abutment ofclaim 29 wherein said sheath is ceramic.
 33. An abutment for mounting aprosthesis tooth on a metal dental implant anchored in bone, saidabutment comprising: a. a central metal core for engaging said implant,said core having a supragingival portion and an enlarged gingivalportion for engaging said implant; b. a metal screw passing through anopening in said core for securing said core to said implant; and c. aceramic sheath surrounding at least a portion of said central coreadjacent an implant end of said abutment and forming an abutment facewhich mounts the distal end of said tooth.
 34. The abutment of claim 33wherein said central metal core is tubular, and said ceramic sheathsurrounds a substantial sub-gingival portion of said tubular core.
 35. Adevice for the reconstruction of a missing or lost tooth, comprising: a.a metal implant portion disposed within the jawbone at the location ofsaid missing or lost tooth for anchoring a prosthesis tooth; b. a metalcore portion for mounting said prosthesis tooth, said core portionabutting and fixed to said implant portion; and c. a ceramic sheathforming an abutment face surrounding said core which mounts saidprosthesis tooth.
 36. In an implant system for the reconstruction ofmissing or lost teeth, said system including a metal implant body and anabutment comprising a metal core, means for anchoring the body in ajawbone so that a portion of the implant system extends from the jawbonethrough the overlying gingiva, means for securing the abutment to thebody, and a detachable prosthesis tooth, the improvement comprising: aceramic sheath surrounding a portion of said metal abutment core andproviding an abutment face which mounts said tooth, and a portion ofsaid sheath below said tooth to be exposed by gingival recession.
 37. Anabutment for supporting a prosthetic tooth on a dental implantcomprising: a metallic core having a bottom portion with a bottom endfor engaging said implant, an upper portion disposed above said bottomportion, said upper portion being narrower than said bottom portion, anda transition cuff between said upper portion and said bottom portion:means for non-rotatably anchoring said abutment on said dental implant;and a ceramic sheath attached to said metallic core, said ceramic sheathbeing located around said upper portion and on said transition cuff,said ceramic sheath including an abutment face for supporting saidprosthetic tooth, a distance between said abutment face and saidtransition cuff being greater than a distance between said transitioncuff and said bottom end.
 38. The abutment of claim 37, wherein saidtransition cuff is curved.
 39. The abutment of claim 37, wherein saidnon-rotational anchoring means includes a screw for engaging a threadedbore in said implant.
 40. The abutment of claim 39, wherein saidnon-rotational anchoring means further includes a polygonal socket insaid metallic core for mating with a polygonal boss on said implant. 41.The abutment of claim 37, wherein said narrower upper portion extends toapproximately the same height as the height of said ceramic sheath. 42.The abutment claim 37, wherein said narrower upper portion extends aboveat least a portion of said abutment face of said ceramic sheath.
 43. Theabutment of claim 37, wherein said distance between said transition cuffand said bottom end is less than the height of said narrower upperportion.
 44. The abutment of claim 37, wherein said upper portion issubstantially cylindrical.
 45. An abutment for supporting a prosthetictooth on a dental implant comprising: a metallic core having a bottomportion for engaging said implant, an upper portion disposed above saidbottom portion, said upper portion being narrower than said bottomportion, and a transition cuff between said upper portion and saidbottom portion; means for non-rotatably anchoring said abutment on saiddental implant; and a ceramic sheath being located around said upperportion and said transition cuff of said metallic core, said sheathbeing attached to said bottom portion, said ceramic sheath including anabutment face for supporting said prosthetic tooth, said sheathextending from said abutment face to a bottom end of said abutment.